A non-invasive and non-systemic method for intradermal prevention OR amelioration of pain from a surgically closed wound is disclosed. The method comprises topical delivery of a local anesthetic to an exterior surface of a surgically closed wound.

The present invention relates to a local method to prevent or ameliorate the pain associated with surgical incision by topically administering a local anesthetic.
The skin is a complex multilayer organ with a total thickness of 2-3 mm. The panniculus adiposus, a variably thick fatty layer, is below the dermis. The dermis is a layer of dense connective tissue that supports the epidermis. The epidermis comprises a layer of epithelial cells and is about 100 xcexcm thick. The epidermis is further classified into a number of layers, of which the outermost layer is the stratum corneum (15-20 xcexcm thick). The stratum corneum comprises highly dense, keratinized tissue and is the skin""s main source of penetration and permeation resistance (Montagna, W. and Parakkal, P. F. (1974) The Structure and Function of Skin, Academic Press, New York and Holbrook, K. A. and Wolf, K. (1993) The Structure and Development of Skin, In: Dermatology in General Medicine, Vol 1, 4th ed., Eds. T. B. Fitzpatrick, A. Z. Eisen, K. Wolff, I. M. Feedberg, and K. F. Austen, McGraw Hill, Inc., New York, pp. 97-145).
Because of the skin""s drug permeation resistance, as little as about 1 percent and usually no more than about 15 percent of a drug in a dermatological formulation is bioavailable (Ghosh, T. K.; Pfister, W. R.; Yum, S. I. Transdermal and Topical Drug Delivery Systems, Interpharm Press, Inc. p. 7).
After a surgical procedure, pain results from pain receptor stimulation. Postoperative or post-traumatic pain is caused by stimulation of sub-dermal sensory nerve receptors (i.e., nociceptors). And trauma is increased over the first 24-48 hours by phases of reactive edema and by release of cytokines and chemo reactive agents.
After a wound is closed by a surgical professional, pain prevention options are limited, especially outpatient pain control and management. Traditionally, for post wound closure pain prevention, opiates and NSAIDs are administered systemically, i.e., throughout the organism via the circulatory system. Topical intradermal pain prevention has seen little application, likely because surgically closed wounds are expected to present a drug permeation barrier similar to intact skin.
Systemic administration of pain relief drugs usually is effected orally or intravenously, The AHCPR Guidelines suggested pain control options include: systemic administration of non-steroidal anti-inflammatory drugs (NSAIDs) or opiates using the traditional xe2x80x9cas neededxe2x80x9d schedule or around-the-clock administration (American Pain Society, 1989).
Systemic pharmacotherapies are, however, accompanied by adverse side effects, particularly with continuous use. With NSAIDs, there is a high risk of gastric disorders, erosions of the stomach lining and the intestinal mucus membrane and bleeding. Administration of opiates and narcotics presents a high dependency risk aside from other undesirable effects, like, respiratory depression, sedation, dizziness, nausea, and constipation. Furthermore, systemic use of these substances while taking other medications can result in detrimental pharmacologic interactions. Of course, pharmacological interactions become more significant in an ambulatory postoperative patient for whom polypharmacy is necessary.
In contrast to prevention of pain with systemic agents, pain can also be treated locally, that is, by delivering the pain reliever directly to the painful area. Thus, for example, a local anesthetic or NSAID might be injected at the pain area.
Local anesthetics reversibly block impulse conduction along nerve axons and other excitable membranes that utilize sodium channels as the primary means of action potential generation. This blocking action can be used clinically to block pain sensation at specific areas of the body (Strichartz, G. R. (Ed.) Local Anesthetics, Handbook of Experimental Pharmacology, Vol. 81, Springer, Berlin/New York, 1987). Furthermore, local anesthetics generally possess a good tissue tolerance, and in some cases, local anesthetics have bactericidal properties, and may impart a positive influence on the regional vessel innervation during wound healing and episodes of.
Traditionally, pain relief with local anestheticsxe2x80x94at least for the more painful wounds, such as surgically closed woundsxe2x80x94involves injection into the area of the nerve fibers to be blocked (Jones M. Gregg AK, Anaesthesia 1999 February; 54(2):200). But with this therapy, the medical professional is confronted with the risk/benefit consideration between the negative effects of systemic absorption versus achieving pain relieving concentrations at the pain site. Systemic absorption of injected local anesthetics is modified by several factors, including dosage, injection site, drug tissue binding. For example, local anesthetic injection to a highly vascular area results in more rapid systemic absorption and thus, adversely, higher drug blood levels are attained. In an analogy to injection, local anesthetics have also been infused directly into open wounds before surgical closure (e.g., U.S. Pat. Nos. 5,272,139 and 5,922,340).
In addition to systemic absorption risk, local injection is painful and invasive and also requires professional administration. Of course, with surgically closed wounds, which are very sensitive, injections should be avoided if possible.
While topical application of local anesthetics might overcome some of the problems associated with injection (especially systemic dangers), this method has not been widely used, mainly, as discussed above, by the difficulty to get significant concentrations through skin barrier. Further advantages of topical administration include improved patient compliance and reversible action (i.e., the action can be reversed by removing the anesthetic from the application site) (Ghosh, T. K.; Pfister, W. R.; Yum, S. I. Transdermal and Topical Drug Delivery Systems, Interpharm Press, Inc. pp. 33-112).
Thus, topical administration of local anesthetics has, in general, only been used to treat minor pain where small concentrations of the anesthetic will suffice. For example, for relief of minor pain from scrapes, skin irritations. Topical administration of local anesthetics is also indicated for topical anesthesia prior to needle insertion (e.g., blood sampling, vaccination, allergy testing), and superficial surgical procedures (Zook et al. U.S. Pat. No. 5,415,866; Royds, R. B. U.S. Pat. No. 5,466,465; Zhange et al. U.S. Pat. No. 5,919,479; and Berkovitch, et al. J. Clin. Pharmacol. 35: 295-297).
In addition to classic local anestheticsxe2x80x94i.e., amide and ester typexe2x80x94several of the more potent NSAIDs have been developed into topical products for local application to minor pain sitesxe2x80x94for example, Cordran(copyright) Tape delivers flurandrenolide for relief of inflammatory and puritic conditions (Oclassen (1995) Cordon Tape Package Insert, Oclassen Pharmaceutical, San Rafael, Calif.).
But, in brief, topical application of local anesthetics is not known to treat the more intense pain associated with wounds after surgical closure. This is likely because a surgically closed wound is expected to present the same permeability difficulties associated with intact skin.
Surgically closed wounds are tightly welded. The most common techniques for closure of open wounds is suturing (with either non-absorbable and absorbable materials) and stapling. These mechanical closure methods provide tension on the skin tissue at the wound border that encourages epithelial tissue to migrate toward the wound and cover it. As the skin heals, the wound becomes even more impenetrable by pharmaceuticals, nonetheless, the pain persists. Also, modern surgical suturing techniques and intraoperative hemostasis, wound treatment has been greatly advanced by the use of suitable supplementary materials, such as tissue glues and adhesives, to accelerate hemostasis as well as to optimize conditions and control of wound closure. Fibrin-based biological glues have proven particularly advantageous over non-biological adhesives because fibrin-based glues mimic the natural coagulation cascade and enhance the healing process.
In short, surgically closed wounds are expected to present a formidable barrier against penetration of topically applied pain relief agents in sufficient concentration to relived the intense pain once the original anesthetic (systemic or locally injected) used in the surgery has worn off.
Thus far a non-invasive and non-systemic treatment for pain resulting from surgically closed woundsxe2x80x94e.g., closed wounds, wherein the wound resulted from a surgical procedure, such as laporasopy or any non-surgical occurrence, such as, accidental knife cuts, etc.xe2x80x94has not been available.
The present invention concerns a non-invasive and non-systemic method for prevention or amelioration of incisional pain resulting from a surgically closed wound. The inventors have found that topically applied local anesthetics can be used to treat the pain associated with a surgically closed wound.
In one embodiment the invention comprises, a method of preventing pain from a surgically closed wound in a subject comprising applying a pharmaceutically acceptable topical drug formulation comprising a therapeutically effective dose of a local anesthetic or a pharmaceutically acceptable salt thereof on or adjacent to an exterior surface of the wound. The wound can be any wound such as an accidental knife cut, preferably the wound resulted from a surgical procedure.
In a preferred embodiment the method of the invention may be used to prevent the pain from surgically closed wounds resulting from laparoscopy, hemiaplasty, breast biopsy, or excision of subcutaneous tumors.
Any local anesthetic can be used with the current invention. Preferred local aesthetics include lidocaine, tetracaine, bupivacaine, prilocaine, mepivacaine, procaine, chloroprocaine, ropivacaine, dibucaine, etidocaine, or benzocaine or any mixtures thereof The most preferred local anesthetic is lidocaine.
In another embodiment, the current invention concerns a patch comprising a local anesthetic in an amount therapeutically effective to prevent or ameliorate pain from a surgically closed wound in a mammal suffering from the pain packaged in association with instructions, the instructions comprising: applying the patch to the surgically closed wound such that the patch covers at least a part of the area of the surgically closed wound.
These and other features, aspects, and advantages of the invention will become better understood with reference to the following detailed description, example, and appended claims.
The present invention may be used to prevent or ameliorate pain from any surgically closed wound by topically applying a local anesthetic in a pharmaceutically acceptable topical drug formulation. The pharmaceutically acceptable topical drug formulation may be contained in a patch.
According to the invention the term xe2x80x9csubjectxe2x80x9d means any mammal, including domesticated mammals, like dogs and cats. Preferably, the subject is a human.
As used herein, the term xe2x80x9clocal anestheticxe2x80x9d means any drug that provides local numbness or analgesia or any drug that provides a regional blockage of nociceptive pathways (afferent and/or efferent). The meaning of xe2x80x9clocal anestheticxe2x80x9d also encompasses drugs not traditionally associated with local anesthetic properties but which have a local anesthetic effect, like NSAIDs (e.g., acetylsalicylic acid, ketoprofen, piroxicam, diclofenac, indomethacin, ketorolac, Vioxx(copyright), and Celebrex(copyright)), opioids as described in U.S. Pat. No. 5,589,480 (e.g., morphine or morphine sulfate), and other agents.
The local anesthetic can be any local anesthetic known or to be developed. The amide and ester type local anesthetics are preferred. Amide type local anesthetics are characterized by an amide functionality, while ester type local anesthetics contain an ester functionality. Preferred amide type local anesthetics are: lidocaine, bupivacaine, prilocaine, mepivacaine, etidocaine, ropivacaine, dibucaine, and mixtures thereof. Preferred ester type local anesthetics are: tetracaine, procaine, benzocaine, chloroprocaine, and any mixture thereof. The most preferred local anesthetic is lidocaine.
When the local aesthetic contains a basic functionality, it may be present in the form of an acid addition salt or as the free base. Preferred salts are the hydrochloride, bromide, acetate, citrate, carbonate or sulfate salts. But preferably, the local anesthetic agent is in the form of a free base. More preferably lidocaine is used in the free base form.
Furthermore, in order to improve the effectiveness and tolerance of the present topically effective therapy, local anesthetics with different pharmacodynamics and pharmacokinetics may be combined in a pharmaceutically acceptable topical drug formulation. A preferred combination of local anesthetics is lidocaine and prilocaine and another preferred combination is lidocaine and tetracaine.
The term xe2x80x9csurgically closed woundxe2x80x9d, as used herein, means any wound that has been closed, such that, the opposing edges of skinxe2x80x94which comprise the woundxe2x80x94have been joined together by a device or material. Preferably, the wound has been closed by a medical professional, such as, a surgeon, doctor, doctors assistant, emergency medical technician, or nurse.
Surgically closed wounds include but are not limited to wounds that have been closed with: sutures (absorbable or non-absorbable, synthetic or natural), staples, and biological glues.
The term xe2x80x9ctopical drug formulationxe2x80x9d means a formulation designed for topical skin application and containing a drug, for example, a formulation in the form of a polymer matrix, cream, gel, emulsion, or ointment.
Application is accomplished by applying the topical drug formulation on or adjacent to an exterior surface of the surgically closed wound. Preferably the topical drug formulation is applied directly to the surface of the surgically closed wound. The pharmaceutically acceptable topical drug formulation of the invention should be applied using a sterile technique.
The term xe2x80x9cdrugxe2x80x9d means a substance used in the diagnosis, treatment, or prevention of a disease or medical condition or an active component of a medication. Of course, the term xe2x80x9cdrugxe2x80x9d encompasses local anesthetics.
As used herein xe2x80x9cpatchxe2x80x9d comprises at least a topical drug formulation and a covering layer, such that, the patch can be placed over the surgically closed wound thereby positioning the patch/drug formulation adjacent to the wound""s surface. Preferably the patch is designed to maximize drug delivery through the stratum corneum, upper epidermis, and into the dermis, and to minimize absorption into the circulatory system, reduce lag time, promote uniform absorption, and reduce mechanical rub-off.
The topical drug formulations and patch systems according to the invention preferably provide controlled release of a local anesthetic agent to the surgically closed wound.
In one embodiment of the invention, the topical drug formulation comprises a carrier system. Pharmaceutically effective carriers include buffered solutions, e.g, hypotonic or buffered saline, liposomes and the like or any other art-known pharmaceutically acceptable topical carrier. More preferred carriers include creams, ointments, oils, plasters, and emulsions. A more complete listing of art-known carriers is provided by reference texts that are standard in the art, for example, Remington""s Pharmaceutical Sciences, 16th Edition, 1980 and 17th Edition, 1985, both published by Mack Publishing Company, Easton, Pa., the disclosures of which are incorporated by reference herein in their entireties.
After application of the topical drug formulation to the surgically closed wound, the wound may be covered with a dressing. The term xe2x80x9cdressingxe2x80x9d, as used herein, means a covering designed to protect a previously applied drug formulation. xe2x80x9cDressingxe2x80x9d includes coverings such as a bandage, which may be porous or non-porous and various inert coverings, e.g., a plastic film wrap or other non-absorbent film. The term xe2x80x9cdressingxe2x80x9d also encompasses non-woven or woven coverings, particularly elastomeric coverings, which allow for heat and vapor transport. These dressings allow for cooling of the pain site, which provides for greater comfort.
In a preferred embodiment of the current invention, the topical drug formulation containing a local aesthetic is contained in a patch that is applied adjacent to the surface of the surgically closed wound. Preferably, the patch components resemble the viscoelastic properties of the skin and conform to the skin during movement to prevent undue shear and delamination.
A patch containing a topical drug formulation has advantages over the simple topical drug formulation alone. One advantage is that the dose is controlled by the patch""s surface area. Other advantages of patches are constant rate of delivery, longer duration of action (the ability of to adhere to the skin for 1, 3, 7 days or longer); improved patient compliance, non-invasive dosing, and reversible action (i.e., the patch can simply be removed).
A patch suitable for use with the invention should contain at least: (1) a backing layer and (2) a carrier formulated with a local anesthetic.
Preferred patches include (1) the matrix type patch; (2) the reservoir type patch; (3) the multi-laminate drug-in-adhesive type patch; and (4) the monolithic drug-in-adhesive type patch; and (Ghosh, T. K.; Pfister, W. R.; Yum, S. I. Transdermal and Topical Drug Delivery Systems, Interpharm Press, Inc. p. 249-297, incorporated herein by reference). These patches are well known in the art and generally available commercially.
For practice of the invention, the matrix type and the drug-in-adhesive type patches are especially preferred. The more preferred drug-in-adhesive patch is the monolithic type.
The matrix patch comprises an anesthetic containing matrix, an adhesive backing film overlay, and preferably, a release liner. In some cases, it may be necessary to include a impermeable layer to minimize drug migration into the backing film (e.g., U.S. Pat. No. 4,336,243, incorporated herein by reference). The anesthetic containing matrix is held against the skin by the adhesive overlay. Examples of suitable anesthetic matrix materials include but are not limited to lipophilic polymers, such as polyvinyl chloride, polydimethylsiloxane, and hydrophilic polymers like polyvinylpyrrolidone, polyvinyl alcohol, hydrogels based on gelatin, or polyvinylpyrrolidone/polyethylene oxide mixtures.
The reservoir type patch design is characterized by a backing film coated with an adhesive, and a reservoir compartment containing a drug formulation preferably, in the form of a solution or suspension, that is separated from the skin by a semipermeable membrane (e.g., U.S. Pat. No. 4,615,699, incorporated herein by reference). The adhesive coated backing layer extends around the reservoir""s boundaries to provide a concentric seal with the skin and hold the reservoir adjacent to the wound.
The monolithic drug-in-adhesive patch design is characterized by the inclusion of the drug formulation in the skin contacting adhesive layer, a backing film and preferably, a release liner. The adhesive functions both to release the anesthetic and adhere the anesthetic matrix to the skin. The drug-in-adhesive system does not require an adhesive overlay and thus the patch size is minimized. Also, drug-in-adhesive type patches are thin and comfortable (e.g., U.S. Pat. No. 4,751,087, incorporated herein by reference).
The multi-laminate drug-in-adhesive patch design further incorporates additional semi-permeable membrane between two distinct drug-in-adhesive layers or multiple drug-in-adhesive layers under a single backing film (Peterson, T. A. and Dreyer, S. J. Proceed. Intern. Symp. Control Rel. Bioact. Mater. 21: 477-478, incorporated herein by reference).
Semi permeable membranes, useful with the reservoir or multi-laminate patch, include thin non-porous ethylene vinyl acetate films or thin microporous films of polyethylene employed in microlaminate solid state reservoir patches.
Adhesives for use with the drug-in-adhesive type patches are well known in the art and selection is readily accomplished by an ordinary practitioner. Three basic types commonly used are polyisobutylenes, silicones, and acrylics. Adhesives useful in the present invention can function under a wide range of conditions, such as, high and low humidity, bathing, sweating etc. Preferably the adhesive is a composition based on natural or synthetic rubber, polyacrylate, polyvinylacetate, polybutylacrylate, polymethylacrylate, polydimethylsiloxane, and hydrogels (e.g., high molecular weight polyvinylpyrrolidone and oligomeric polyethylene oxide). The most preferred is polyacrylate.
Suitable release liners include but are not limited to occlusive, opaque, or clear polyester films with a thin coating of pressure sensitive release liner (e.g., siliconefluorsilicone, and perfluorcarbon based polymers.
Backing films may be occlusive or permeable and are derived from synthetic polymers like polyolefin oils polyester, polyethylene, polyvinylidine chloride, and polyurethane or from natural materials like cotton, wool, etc. Occlusive backing films, such as synthetic polyesters, result in hydration of the outer layers of the stratum corneum while non-occlusive backings allow the area to breath (i.e., promote water vapor transmission from the skin surface). More preferably the backing films are occlusive and comprised of a polyolefin oil.
Additionally, in order to make the present therapy safer, use-specific, and more manageable overall, the present patch may have such a geometric shape such that it corresponds to the special conditions of the application field. Thus, the shape of the patch can be flat or three-dimensional, round, oval, square, and have concave or convex outer shapes, or the patch or bandage can also be segmented by the user into corresponding shapes with or without additional auxiliary means.
Selection of the appropriate dosage for the application site is an important consideration. The rate of intradermal anesthetic delivery from the topical drug formulation or patch is a function of skin permeability, and skin permeability has been shown to vary between anatomical sites depending on the thickness of the stratum corneum. For example, the permeability, in general, increases in order from planter foot arch, lateral ankle, palm, ventral forearm, dorsal forearm, back, chest, thigh, abdomen, scalp, axilla, forehead, and scrotum (Wester, R. C. and Maibach, H. I. (1989) Regional variation in Percutaneous Absorption: In Percutaneous Absorption, Mechanism, Methodology, Drug Delivery, 2nded., Eds. R. L. Bronaugh and H. I. Maibach, Marcel Dekker, Inc., New York, pp. 111-119 (incorporated herein by reference)). Of course, the dosages and dosing frequency will be determined by a trained medical professional, and will depend upon many factors such as wound location, size, severity, and the type of surgical closure.
Topical formulations in the form of a gel, cream, or ointment, containing the local anesthetic may be applied adjacent to the surgically closed wound such that the wound and a portion of its surrounding area are covered. The amount of local anesthetic in the topical drug formulation will generally be in the range of about 1 percent to about 25 percent (percents are by weight), preferably, in the range of about 2 percent to about 20 percent, most preferably about 3 percent to about 5 percent.
With gels, creams, or ointments, typically 1 to 4 applications are required per day. Generally, about 0.5 g/cm2 to about 5 g/cm2, preferably 1 g/cm2 to about 2 g/cm2 of the topical drug formulation is applied to and around the wound. Preferably a lidocaine topical formulationxe2x80x94wherein the lidocaine concentration is about 1 percent to about 10 percent, more preferably about 2 percent to about 5 percentxe2x80x94is applied to the surgically closed wound in an amount of about 1 g/cm2 to about 2 g/cm2 in the area of and around the wound. After application, preferably, the wound is covered with a dressing.
When a combination of local anesthetics is used, the preferred combination is a eutectic mixture of lidocaine and prilocaine. In such a mixture, the amount of lidocaine can range from about 1 percent to about 40 percent, preferably from about 2 percent to about 20 percent, and more preferably from about 3 percent to about 5 percent and the amount of prilocaine can range from about 0.5 percent to about 40 percent, preferably from about 2 percent to about 20 percent, and more preferably about 3 percent to about 5 percent. Preferably the mixture is formulated as an oil in water emulsion.
Another preferred local aesthetic combination is a mixture of lidocaine and tetracaine. In such a mixture, the amount of lidocaine can range from about 1 percent to about 40 percent, preferably from about 2 percent to about 20 percent, and more preferably from about 3 percent to about 5 percent and the amount of tetracaine can range from about 0.5 percent to about 40 percent, preferably from about 2 percent to about 20 percent, and more preferably about 3 percent to about 5 percent. Preferably the mixture is formulated as an oil in water emulsion.
When a patch is used to relieve the pain from a surgically closed wound, the dosage of the local anesthetic required to achieve pain relief is determined by the active surface area of the medicated portion of the patch in direct contact with the skin. Several dosage strengths are advantageous depending upon the severity of the wound. In general, a physician may begin dosing with a low or intermediate strength patch and then, depending upon the effectiveness, adjust the dosage up or down by prescribing a patch of higher or lower anesthetic concentration or a patch of larger or smaller surface area, or, in some cases, multiple patches.
In general, the anesthetic will comprise from about 0.5 percent to about 40 percent by weight of the patch, preferably from about 10 percent to about 30 percent, more preferably from about 15 percent to about 25 percent, and most preferably from about 18 percent to about 22 percent by weight of the patch. Fresh patches may be applied multiple times per day, but, preferably, a fresh patch is applied about every 18 to about every 48 hours. More preferably, the patch is applied daily.
In another embodiment of the current invention, the local anesthetics used in the topical drug formulations and patches are in a form capable of transport into the dermis. Administration of these drug formulations according to the invention may involve the use of excipients. Any pharmaceutically acceptable excipient is suitable. For example, penetration enhancers, plasticisers, antioxidants, colorants, preservatives, antibiotics, etc.
The method of the invention may be used with other conventional systemic pain relief therapies, including but not limited to analgesics, opiates, and narcotics.
When practicing the invention, medicinal agents or their salts may be incorporated into the topical drug formulation or into the appropriate fraction or layer of the patch. For example, antifungal agents such as ciclopirox, chloroxylenol, triacetin, sulconazole, nystatin, undecylenic acid, tolnaftate, miconizole, clotrimazole, oxiconazole, griseofulvin, econazole, ketoconozole, and amphotericin B may be incorporated. Antibiotic agents such as mupirocin, erthromycin, clindamycin, gentamicin, polymyxin, bacitracin, silver sulfadiazine, and the like. Antiseptic agents such as iodine, Povidine-iodine, benzalkonium chloride, benzoic acid, chlorhexidine, nitrofurazone, benzoyl peroxide, hydrogen peroxide, hexachlorophene, phenol, resorcinol, and cetylpyridinium chloride likewise could be incorporated into the topical drug formulation or the patch. Furthermore, anti-inflammatories such as hydrocortisone, prednisone, triamcilolone, betamethasone, dexamethasone, and the like may be incorporated.
In another embodiment, penetration enhancers can be included in the topical drug formulation or patch, to optimize local anesthetic delivery into and through the skin (Ghosh, T. K. et al. (1993), Pharm. Tech. 17(3):72-98; Ghosh, T. K. et al. (1993), Pharm. Tech. 17(4): 62-89; Ghosh, T. K. et al. (1993), Pharm. Tech. 17(5):68-76). The penetration enhancer should be pharmacologically inert, non-toxic, and non-allergenic, have rapid and reversible onset of action, and be compatible with the drug formulation (Pfister et al. Pharm. Tech. 14(9):132-140, incorporated herein by reference).
Useful penetration enhancers include but are not limited to ethyl alcohol, isopropyl alcohol, or octolyphenylpolyethylene glycol. More preferred penetration enhancers include oleic acid, polyethylene glycol 400, propylene glycol, N-decylmethylsulfoxide, fatty acid esters (e.g., isopropyl myristate, methyl laurate, glycerol monooleate, and propylene glycol monooleate); and N-methyl pyrrolidone.
In yet another embodiment of the current invention, agents may be included to prolong the anesthetic effect, such as, a glucocorticosteroid (see, U.S. Pat. No. 5,922,340) or a vasoconstrictors, such as a catecolamine.
The present invention and its many attendant advantages will be understood from the foregoing description and it will be apparent that various changes in form, construction and arrangement of the parts there of may be made without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described are merely exemplary embodiments thereof.

Local prevention or amelioration of pain from surgically closed wounds


The concept of caller identification (ID) may be enhanced by taking advantage of video by allowing a call recipient to see who is calling on an incoming video call. The call recipient may be allowed to make a decision to accept or decline the incoming video call based upon who the call recipient sees (e.g. through a live video stream) attempting to contact them.

Session Initiation Protocol (SIP) is an IETF-defined signaling protocol widely used for controlling communication sessions such as voice and video calls over Internet Protocol (IP). SIP can be used for creating, modifying, and terminating two-party (unicast) or multiparty (multicast) sessions. Sessions may consist of one or several media streams. Other SIP applications include video conferencing, streaming multimedia distribution, instant messaging, presence information, file transfer, and online games. SIP protocol is an Application Layer protocol designed to be independent of the underlying Transport Layer; it can run on Transmission Control Protocol (TCP), User Datagram Protocol (UDP), or Stream Control Transmission Protocol (SCTP). SIP is a text-based protocol, incorporating many elements of the Hypertext Transfer Protocol (HTTP) and the Simple Mail Transfer Protocol (SMTP).

Method to preview caller in a video conference session


Cable closures and methods are provided for enclosing a cable. The cable closure includes two half shells together forming an enclosed space for housing a cable, and a sealing strip positioned between peripheral regions of the half shells, at least one of the shells having a removable portion to provide a cable entry port. A cable sealing device may be positioned at the cable entry port such that a seal is provided between the sealing strip and each half shell and a cable entering through the port.

This invention relates to a cable closure, by means of which environmental protection may be provided around a cable splice, termination or other cable portion. The invention may be used with power cables, CATV cables or telephony or other communications cables. The invention is likely to find most use in protecting splices in, and terminations of, optical fibre cables.
The use of closures for environmental sealing of cable splices is of course well known. Cables are produced in finite lengths and therefore lengths of cable frequently need to be joined together. The function of a closure is to provide a seal that bridges the jackets of the spliced cables. A closure may also provide other functions in addition to environmental protection, such as mechanical protection and axial-pull strength. Closures may be used around simple end-to-end splices between cables, but frequently more complex splices require sealing. For example, a large cable containing many conductors (by which term I include optical fibres as well as electrical conductors) may be split into two or more smaller cables. Ultimately, a cable will be effectively terminated where it is broken down to single conductors or small groups of conductors. Such terminations also require cable closures to protect them.
It is frequently necessary to install a cable closure around a cable splice (or termination) where access to ends of the cables is not available. In such circumstances the closure clearly cannot be permanently of closed cross-section: the closure needs to be xe2x80x9cwrapped aroundxe2x80x9d the cables, rather than slid onto the cables from one end. This term xe2x80x9cwrap aroundxe2x80x9d derives from cable closures that were formed from flexible sleeves or longitudinally-slit tubes. It is, however, a general term that merely refers to the capability of installation around a cable at some point between its ends. Thus, the term includes substantially rigid half shells that are assembled around the splice. The shells may be hinged or otherwise linked together by moulded-in strips or by tapes or living hinges etc. The term xe2x80x9chalf shellsxe2x80x9d does not imply any particular shape, and the two half shells may be different or generally similar in shape to one another. Thus, each half shell will have a periphery that abuts the periphery of the other half shell, and each will have a hollow body portion, roughly semi-circular in cross-section, so that when the two half shells are brought together they define a roughly rectangular or circular cylindrical enclosed space within which the splice will lie. Half shells may, however, differ from one another, so that one might be described as a base plate, and the other as a cover. These terms xe2x80x9cwrap aroundxe2x80x9d and xe2x80x9chalf shellsxe2x80x9d are well-known in the art.
Many cable closures have been proposed that make use of half shells. Unfortunately, many problems remain. The performance requirements of a closure are very difficult to meet. The problem arises largely because a closure must be very quick and easy to install, usually with unskilled labour, and under difficult conditions, but must meet very stringent performance specifications. As a general rule a cable closure is expected to have a life time comparable to that of the cables which it protects, typically twenty or more years. Cables are generally situated out of doors and are subjected to extremes of temperature and humidity. Various tests have been devised to mirror this long-term performance. Although different tests are applicable to different cables in different situations, typical tests involve pressurisation of the closure whilst it is subjected to temperature cycling, often under wet or humid conditions. A closure is expected not to leak for a certain number of such cycles. Clearly, closures of the half shell design start out at a disadvantage because a seal must be provided between the half shells as well as between the incoming and outgoing cables and each half shell. A particularly severe problem arises at the region where a seal between the half shells meets a seal between the cables and each half shell. This region is known as the xe2x80x9ctriple pointxe2x80x9d. It can therefore be seen that design of such a closure is a difficult matter.
The difficulties are, as usual, increased by the need for low cost. The requirement for low cost means that it is not possible to supply different designs of closure for each cable size and for each splice or termination configuration. Thus, a single design of closure must be able to accommodate, for example, a simple in-line splice between two cables, a butt splice between two cables (where the two cables lie side-by-side), and various configurations, such as xe2x80x9cone in-two outxe2x80x9d where one cable enters one end of a closure and two leave at an opposite end. In order to accommodate a range of splice configurations, one may decide to provide a closure that has four cables seals, two at each end. Cable seals are, unfortunately, expensive and such a closure would need to be provided with four such seals. Each of these seals would need to be capable, not only of sealing to an incoming cable, but also be capable of being closed in case the full compliment of cables was not to be employed. The present invention provides a particularly simple and elegant solution to these problems.
Before the invention is described in detail it may be worth noting some prior art closures of the half shell type. U.S. Pat. No. 5,322,973 discloses an aerial closure for protecting a cable splice. It has a central header portion and wing-like housing segments that may enclose the splice. The wing-like housing segments may be raised to provide access to the splice. Each end of the closure has a seal assembly for sealingly engaging the ends of the incoming cables. These assemblies have concentrically circular and corrugated features thereon so that an appropriately size hole may be cut to allow entry of 1, 2 or 3 cables of various sizes.
U.S. Pat. No. 4,805,979 discloses a fibre optic splice closure comprising a base to which a cable may be anchored, and a cover which overlies the base. Seals are provided around the cables at the position where the base meets the cover.
U.S. Pat. No. 4,492,816 discloses half shells for forming a cable splice. Half shells have flanges which abut one another in the assembled configuration. The adjacent flanges define a duct into which sealing material in the form of a paste may be introduced. Opposite ends of the resulting closure are provided with jaws which clamp against the incoming cables. Two jaws define between them a chamber which communicates with the sealing duct by means of a channel formed around the entire periphery of a jaw adjacent to the chamber.
EP 0543350 discloses a cable enclosure formed from a base and a cover which are secured together by bolts through flanged portions thereof. Various cable guide sections are located at the interface between the base and the cover.
GB 1260273 discloses a housing for electrical connections, which comprises a cylindrical central part and end parts that form a seal between the central housing and each incoming cable. The end parts are moulded to provide a number of cable entry ports. The ports are initially blind. The extreme ends of the ports are cut off as and when required to allow cables to pass through. The ports are heat-shrinkable so that after insertion of a cable a port can be shrunk to make sealing contact with it.
U.S. Pat. No. 5,109,467 discloses an optical fibre interconnect cabinet in the form of a box with a lid. The side walls of the box are provided with slots which can receive removable blanks. With the blanks in place, and the lid closed, the box is sealed. With the lid open, a blank can be removed to provide a port for cable entry.
Whilst each of those prior art designs provides some of the benefits that I now seek, each unfortunately suffers from one or more problems. For example, some of the designs are not fully xe2x80x9cwraparoundxe2x80x9d, some are not suited for environmental protection out of doors, some are too complex and expensive, and some do not provide the desired flexibility in terms of cable size and/or cable configuration.
I have now designed a cable closure that can provide excellent sealing for a variety of cable configurations, and which allows quick and simple installation.
Thus, the invention provides a cable closure comprising:
1) two half shells that together form an enclosed space for housing a cable (more particularly some part of a cable such as a termination or splice),
2) a sealing strip (preferably formed of a resilient material such as a rubber or a synthetic elastomer) positioned between a peripheral region of each half shell such that, when the half shell are brought together, said space can be sealed;
3) at least one of the shells having a removable portion that, when removed, provides a cable entry port between the two shells, the sealing strip providing a seal between that portion and the other shell (preferably a removable portion of the other shell when, as is preferred, each shell is provided with a removable portion).
The invention also provides a method of enclosing a cable, which comprises:
a) providing a cable closure as defined above;
b) removing said removable portion;
c) removing that part of the sealing strip that provided a seal between said removable portion and said other shell; and
d) bringing the half shells together around the cable such that a cable passes through the port provided by removal of the removable portion.
One of the half shells may have the form of a base and the other the form of a cover, or each half shell may have a generally hollow region which together form said space. Thus, each half shell may be, for example, substantially semi-circular, semi-rectangular or semi-elliptical, in cross-section such that when the half shells are brought together a generally cylindrical space is formed that is substantially circular, substantially rectangular particularly with rounded corners or substantially elliptical in cross section. In general it will be a desirable for each half shell to be formed, for example by moulding, from a single piece of material. Each half shell may, however, comprise two or more parts joined together, but this has the disadvantage that seals between those parts must be provided.
Where I refer to the sealing strip being positioned between xe2x80x9cperipheralxe2x80x9d regions of the half shells I simply mean that the sealing strip is towards the outside of the shells, although it need not of course be at the extreme edge. In general, the sealing strip will lie between peripheral flanges or edge walls of the half shells, which flanges or edge walls may extend outwardly of the sealing strip for example to provide means by which the half shells can be held together. Such means may comprise a bolt that passes through holes in the flanges or edge walls. It will be understood that it is desirable that such holes be provided outwardly of the sealing strip since otherwise a leak path into the splice case could exist via the holes.
I refer above to the space within the closure being capable of being sealed when the shells are brought together. This is because some additional sealing means or sealing operation may be required. However, in general, sealing between the half shells will result directly from the half shells being brought together with the sealing strip between them, although some fixing means such as the bolts mentioned above may be required to prevent the half shells from separating particularly if the closure is to be pressurised. Thus, the sealing strip preferably follows a substantially closed path around the periphery of the half shells. The sealing strip is preferably in one piece along its length, and may be continuous.
Complete sealing of the space within the closure will of course usually require some additional seal to be provided between incoming cables and the ports through which they enter. In general, a cable sealing device will be provided that is of annular shape, the outside surface of the annulus sealing against the internal surface of the port, and the inner surface of the annulus sealing against the external surface of the cable. Thus, the cable sealing device effectively fills any gap between the cable and the port through which it enters. The design of such cable sealing devices presents its own difficulties. These difficulties result in part from the need to be able to seal to cables of different sizes, since there will be some size variation even between cables of one nominally standard size. Furthermore, the cable sealing device needs to seal not only to the cable and to the surrounding half shells (where they define the port), but also to the sealing strip. This is the xe2x80x9ctriple pointxe2x80x9d problem referred to above. The cable closure of the invention is able to overcome this problem in a particularly elegant way. Thus, I prefer that at least one of the half shells (preferably both) is shaped to define, adjacent and inwardly of the port, a chamber for receiving a cable sealing device; and that the sealing strip run along opposed longitudinal sides of said chamber such that, when the sealing device is in the chamber, the strip at each said side contacts each half shell and the cable sealing device.
In preferred designs of the closure at least two said removable portions are provided side-by-side. A particularly preferred closure is designed to provide four cable entry ports, two side-by-side at each end. The closure may be supplied to the customer with one (or more) ports already open, that is with one (or more) potential removable portions being absent. The precise design will of course depend on the cable configurations possessed by the customer. Therefore, I prefer the closure to have at least two side-by-side ports, whether or not both of the ports in question have removable portions that would close them. I prefer that at least one of the half shells be shaped to define adjacently inwardly of each said port a chamber for receiving a cable sealing device; and that the sealing strip run along opposed longitudinal sides of each chamber such that, when a sealing device is in each chamber, the sealing strip at each said side contacts each half shell and the respective sealing device; and that separate portions of the sealing strip run between the chambers along each of the adjacent longitudinal sides. An alternative is possible; it would be possible for a single portion of sealing strip to run between the two side-by-side chambers. That single portion would therefore be shared by the two chambers.
That alternative arrangement is, however, less satisfactory because it would need to be rather wide, or the two chambers to be rather close, if that single portion of sealing strip were to contact both sealing devices.
These separate portions of sealing strip are preferably joined together towards an inward end of the chambers. In that way the seal is completed. Also, such a design allows the two half shells to be joined together by the means of, for example, bolt that passes through holes in the half shells; the holes would be positioned between the separate portions of sealing strip and outwardly of the position at which they are joined. In this way, the holes for the bolt do not provide a leak path into the splice case.
I prefer that the removable portion that gives rise to the cable port be an integral part of a half shell, although it may initially be separate and later bonded or otherwise sealing fixed to the half shell. The port preferably is formed substantially equally in each half shell, and therefore each half shell preferably has a said removable portion, both of which are to be removed to define the port.
In order that the cable sealing device form a good seal to the half shells, I prefer that the chambers (which will usually be defined by the inside surfaces of each half shell) be wholly concave in cross-section. Clearly, any irregularities in the curvature of the chamber will make a reliable seal difficult. If the cable sealing device is to seal a single cable then the external surface of the sealing device will preferably be substantially circular. However, I prefer that each sealing device be capable of sealing at least two cables, more preferably two cables side-by-side. In this case the cable sealing device need not be of simple annular shape, but may have, say, the shape of two annuli side-by-side with the roughly triangular spaces between them filled in. Overall, in cross-section the cable sealing device may be substantially elliptical. However, a circular cross-section may still be appropriate, particularly if four cables are to be sealed. Clearly, the chambers for the sealing device should have a cross-section or shape that corresponds to the sealing device, and will in general therefore be substantially circular or substantially elliptical in cross-section. The chambers may be provided with some fixing means such as one or more lugs or flanges to prevent axial movement of the sealing device.
The cable sealing device may be of the general design and construction disclosed in WO 90/05401 (N. V. Raychem S. A.). Thus, the sealing device may comprise along an axis thereof first and second end parts and a sealing material between them, the first and second ends parts and the sealing material each allowing a cable to pass through them, the device having means to bring the first and second end parts together thereby putting the sealing material under compression axially, and causing it to be displaced radially to contact a cable therein and the chamber therearound. In general, the first and second ends parts and the sealing material will be provided with an axial hole through which the cable can pass. Also, the first and second end parts and the sealing material may be provided with a radial slit that extends from their outer surface to said hole, which slit can be opened out to allow the sealing device to be xe2x80x9cwrapped aroundxe2x80x9d the cable. A preformed hole need not be provided in the sealing material since it may be possible to rupture the sealing material by pushing the cable through it.
The means that bring the first and second end parts together may comprise a nut and a bolt, one of which is fixed to one end part and the other of which bears against the other end part such that when they are relatively rotated the parts move together. Resilient means such as a spring, preferably a coiled compression spring, may be provided to bias resiliently together the first and second parts, thus maintaining the sealing material under compression during the service life of the closure.
The sealing material preferably comprises a gel, but other materials such as rubbers or mastics may be used. A gel is a liquid-extended polymer composition preferably having a cone penetration value (measured by a modified version of ASTM D217) within the range from 30 to 400 (10xe2x88x921 mm), and an ultimate elongation (measured by ASTM D412) greater than 100%, and preferably also with substantially elastic deformation to the elongation of at least 100%. The composition may contain three-dimensional cross-linked molecular formations, or merely behave as if it contains such molecular formations.
Useful compositions may be provided comprising at least 500 preferably at least 1000 and preferable not more than 5000 parts by weight of an extender liquid per 100 parts by weight of block copolymer or other polymer. Preferred block copolymers are those based on styrene and olefines such as ethylene and butylene. Particularly useful gels may be made using styrene-ethylene-butylene-styrene block copolymers such as those marketed by Shell under the trade name xe2x80x9cKratonxe2x80x9d. Such gels are disclosed in WO 90/05401 referred to above.
The sealing strip may be made of any suitable material, particularly a resilient material such as a rubber or synthetic elastomer. Examples include solid or hollow rubber, rubber foam and rubber gel. Such materials may be used in combination with other materials, for example a mastic, gel or other sealant. In this way, one component may provide a resilient bias and another component may be more deformable and be used to make intimate contact with the various surfaces. For example, a strip (of any suitable cross-section) of resilient material may be positioned in a channel or groove in one or both of the half shells. If desired, a sealing strip may be positioned in each half shell so that the two sealing strips contact one another when the two half shells are brought together. I prefer that the sealing strip or strips be continuous lengthwise (before a part is removed after removal of the removable portions of the half shells) in the region of the removable parts and along the sides of the chambers adjacent those removable parts. More preferably I prefer that the sealing strip (or each strip if one is positioned initially in each half shell) be unbroken along its length for the whole closure. However, in certain circumstances it may be desirable to use separate strips at each end of the closure.


A novelty bar of soap containing an electro-mechanical vibrating mechanism. Within a housing is disposed an electric motor that rotates a weight from an eccentric point. Two reed switches are connected in parallel within the housing. Two alkaline batteries are also provided in the housing. The reed switches selectively power the electric motor with the batteries when at least one of the reed switches is closed. A body of soap surrounds the housing forming a bar of soap. Within the housing, one of the reed switches is disposed proximate the top of the housing. The other reed switch is disposed proximate the bottom of the housing. As such, regardless of how the bar of soap is oriented when placed down, one of the reed switches is positioned near the surface or which the bar of soap is resting.

1. Field of the Invention
The present invention relates to bars of soap that are used for bathing. More particularly, the present invention relates to bars of soap that have secondary functions and/or components traditionally not associated with soap.
2. Description of the Prior Art
Soap has been in existence in various forms for hundreds of years. One of the most popular forms of soap is that of a bar. A bar of soap is popular because it is easy to handle and manipulate while bathing. The bar of soap is traditionally made of pure soap and other water soluble ingredients. As such, the soap continues to function as soap until the bar is completely dissolved, thereby producing no waste product that must be thrown away.
Bars of soap have been manufactured in many different sizes and shapes. Over the years, novelty bars of soaps have been molded into many secondary items, such as flowers, seashells, animals and the like. However, regardless of what form the soap is molded into, the bar of soap is almost always made of totally dissolvable ingredients. As such, when the soap is used, the configuration of the bar of soap erodes away until nothing is left.
There are some instances in the prior art where electronic assemblies have been added to bars of soap. In such prior art products, an electronics module is placed in the center of the soap and the soap is used until the electronics module is exposed. One such prior art device. is shown in U.S. Pat. No. 5,125,398 to Horton, entitled Personal Hygienic Massage Bar. In the Horton patent, a vibrating device is positioned in the soap. However, whenever electronics are added to soap, there must be included some way to selectively activate the electronics within the soap after the soap is purchased.
In the cited Horton patent, a slot is provided in the soap near the battery. A plastic tab is placed in the slot and prevents the battery from making electrical contact within the soap. Once the soap is purchased, the tab is removed and the battery is activated. To prevent the vibrating mechanism from running all the time, a motion sensor and a timing circuit are provided that automatically shuts the vibrating mechanism off after a predetermined period of time.
There are many disadvantages to providing such electronics within a bar of soap. First, the use of a slot in the bar of soap for a plastic pull tab, provides an opening through which water can travel into the electronics module within the soap. Once the electronics are exposed to water, the electronics short out and the electronics module within the soap stops working.
Second, even if water does not get into the electronics assembly, within the soap, the use of motion sensors and timing circuits makes the electronics assembly large, complicated and expensive to manufacture. The larger the electronics module is, the more room the electronics module takes within the soap. This is especially true with a vibrating mechanism, which tends to be large. As can be seen from the Horton patent, the vibrating mechanism takes up most of the volume of the bar of soap. Accordingly, after only a very short period of use, the vibrating mechanism within the bar of soap can become exposed.
A third disadvantage of the vibrating mechanism used in the Horton patent is that the vibrating mechanism requires a large supply of electrical power. Vibrating mechanisms contain motors. Motors require electricity to operate. However, in the prior art, since the vibration mechanism itself tends to be large, small batteries are used to preserve space. Small specialty batteries, such as lithium and nickel-cadmium batteries are typically used since these are the only small batteries that can meet the power requirements of the vibrating mechanism. Such batteries are smaller than alkaline batteries, but are far more expensive. As such, by using small specialty, batteries, the price of the vibrating mechanism is greatly increased. Soap is a disposable item that lasts only a Short period of time. As such, the electronics within the soap must be able to outlast the soap, yet be inexpensive enough not to add significantly to the cost of the soap.
Simplified electronic assemblies have been added to soap in an attempt to limit the disadvantages stated above. For example in U.S. Pat. No. 4,861,505 to Farman, a sound producing assembly is provided in a bar of soap that is activated when the bar of soap is removed from a magnetic soap dish. Although such assemblies eliminate the need for pull tab openings and timing circuits, such prior art assemblies only work when the soap is oriented in a proper way with respect to the soap dish. If the soap is placed in the soap dish upside down or backward, the electronics assembly within the soap is not deactivated. In the Farman patent, the proper orientation of the soap is maintained by referencing an insignia formed in the soap. However, as is well known, the insignia on a bar of soap soon washes away. Once it does, the bar of soap can easily be misplaced and continue to operate unattended until the battery runs out.
A need therefore exists for a bar of soap that contains an electronic assembly, where the electronic assembly is water proof, very inexpensive, small, long lasting, uses conventional batteries and can be easily deactivated when not in use. This need is met by the present invention as is described and claimed below.
The present invention is a novelty bar of soap. The bar of soap has an external layer of soap, and therefore functions as a bar of soap. However, contained within the bar of soap is an electro-mechanical vibrating mechanism. The electro-mechanical vibrating mechanism is contained in a water tight housing that is set into the center of the bar of soap. Within the housing is disposed an electric motor. The electric motor rotates a weight from an eccentric point, thereby causing vibration. Two reed switches are connected in parallel within said housing. Two alkaline batteries are also provided in the housing, where the reed switches selectively power the electric motor with the batteries when at least one of the reed switches is closed. A body of soap surrounds the housing forming a bar of soap.
Within the housing, one of the reed switches is disposed proximate the top of the housing. Similarly, the other reed switch is disposed proximate the bottom of the housing. As such, regardless of how the bar of soap is oriented when placed down, one of the reed switches is positioned near the surface on which the bar of soap is resting. By providing a magnet on such a resting surface, the vibrating mechanism can be selectively deactivated every time it is placed down on the resting surface without regard for the orientation of the bar of soap.

Novelty bar of soap having low cost electro-mechanical vibrating assembly


The present invention provides a method and device for restoring individual patient joint kinematics using minimally invasive surgical procedures. The instrumentation of the invention sculpts the articular surface of a first bone that normally articulates in a predetermined manner with a second bone. The instrumentation includes a bone sculpting tool and a mount for attaching the tool to the second bone. The implant system is comprised of implants that provide intraoperative surgical options for articular constraint and facilitate proper alignment and orientation of the joint to restore kinematics as defined by the individual patient anatomy.

A joint generally consists of two relatively rigid bony structures that maintain a relationship with each other. Soft tissue structures spanning the bony structures hold the bony structures together and aid in defining the motion of one bony structure to the other. In the knee, for example, the bony structures are the tibia and the femur. Soft tissue such as ligaments, tendons, menisci, and capsule provide support to the tibia and femur. A smooth and resilient surface consisting of articular cartilage covers the bony structures. The articular surfaces of the bony structures work in concert with the soft tissue structures to form a mechanism that defines the envelop of motion between the structures. Within a typical envelop of motion, the bony structures move in a predetermined pattern with respect to one another. When fully articulated, the motion defines a total envelop of motion between the bony structures. The soft tissue structures spanning the knee joint tend to stabilize the knee in a transverse plane. This transverse stability enables the bony structures to slide and rotate on one another in an orderly fashion.
The articular surfaces are subject to a variety of diseases, accidents and the like that cause the surfaces to be damaged. A common disorder of joints is degenerative arthritis. Degenerative arthritis causes progressive pain, swelling, and stiffness of the joints. As the arthritic process develops, the joint surfaces wear away, resulting in contractures of the surrounding soft tissues that provide stability to the joint. Changes in the articular surfaces resulting from arthritis decrease stability and increase the translation of the joint.
Treatment of the afflicted articular bone surfaces depends, among other things, upon the severity of the damage to the articular surface and the age and general physical robustness of the patient. The end result commonly necessitates joint replacement surgery wherein the articulating elements of the joint are replaced with artificial elements commonly consisting of a part made of metal articulating with a part made of ultra high molecular weight polyethylene (UHMWPE).
A relatively young patient with moderate to severe degeneration of the knee joint is often treated with drug therapies. While drug therapies may temporarily provide relief of pain, progression of the disease, with resulting deformity and reduced function, ultimately necessitates surgery. Alternative treatments such as nonsteroidal anti-inflammatory drugs, cortisone injections, and arthroscopic debridement similarly provide only temporary relief of symptoms.
In severe situations, the entire articular surface of a bone may be replaced with an artificial surface, as, for example, when condyles at the distal end of the femur are largely replaced with a prosthetic device having polished metal condyles and the tibial plateau is replaced with a plastic bearing that may be supported by a metal component. Joint replacement surgery has become a proven and efficacious method of alleviating pain and restoring function of the joint.
Current methods of preparing the intraarticular rigid elements of a joint to receive components as in joint replacement surgery involve an extensive surgical exposure. The exposure must be sufficient to permit the introduction of guides that are placed on, in, or attach to the joint, along with cutting blocks to guide the use of saws, burrs and other milling devices, and other instruments for cutting or removing cartilage and bone that subsequently is replaced with artificial surfaces. The distal end of the femur may be sculpted to have flat anterior and posterior surfaces generally parallel to the length of the femur, a flat end surface normal to the anterior and posterior surfaces, and angled flat surfaces joining the above mentioned surfaces, all for the purpose of receiving a prosthetic device.
A full joint replacement, using the example of the knee joint, also requires the proximal end of the tibia to be sculpted to receive a prosthesis having a generally upwardly facing bearing surface mimicking the normal tibial bearing surface and designed to articulate with the condylar surfaces of the femoral prosthesis. Typically, this surgery is performed with instruments or guides to orient cutting blocks, such that the preparation of the bone is in concordance with the correct alignment of the limb and the parts are correctly oriented in both coronal and sagittal positions. The guides are placed on exposed bones and generally reference anatomical points on that bone to establish a resection plane. For instance, with total knee replacement, arthroplasty guides are used by referencing, for example, the intramedullary cavity and the epicondylar and posterior condylar axes.
Knee joint prosthesis of the type referred to above are well known, and are described, for example, in Caspari et. al., U.S. Pat. Nos. 5,171,244, 5,171,276 and 5,336,266, Brown, U.S. Pat. No. 4,892,547, Burstein et al., U.S. Pat. No. 4,298,992, and Insall et. al., U.S. Pat. 6,068,658.
Substantial effort has been made to provide appropriate degrees of curvature to the condyles. For example, the earlier mentioned U.S. Pat. Nos. 5,171,276, 4,298,992 and 6,068,658 show that the radius of curvature in the anterior-posterior direction of the condyle of a femoral prosthesis may be somewhat greater near the anterior portion of the condyle than near the posterior portion. Kester et al., U.S. Pat. No. 5,824,100 teaches that a portion of this curvature of the condyle may be formed about a constant radius having its origin along a line between the lateral and medial collateral ligament attachment points on the femur.
Historically, a variety of modular prosthetic joint implants have been developed. The following descriptions of modular implants relate specifically to the knee. Early designs for knee implants, called polycentric knee implants, were developed with separate components for the medial and lateral compartments. Additionally, modular fixed-bearing knee implants having a polyethylene insert that is held relatively rigidly in place have been developed. Alternately, there are mobile bearing knee implants wherein the polyethylene bearing is designed to slide or move with minimal or no constraint on a tibial baseplate. Furthermore, both meniscal bearing and fixed bearing knee implants have been developed including either separate polyethylene bearings or a single polyethylene bearing that resides on a metallic tibial baseplate. While implant systems have been developed with fixed bearing elements or mobile bearing elements on the medial and lateral sides of the tibiofemoral joint, systems have not been developed having a combination of a fixed bearing on one side and a mobile bearing on the other side of the tibiofemoral joint.
Mobile bearing tibial implants may be configured to be more congruent with the femoral side of a knee arthroplasty, yielding lower contact stress. The resultant lower contact stress reduces the. possibility of damage sometimes encountered with some fixed bearing designs wherein the yield strength of the bearing material is exceeded. In general, fixed bearing implant designs are. less difficult to properly align and balance than mobile bearing designs. Mobile bearing designs are frequently desirable to reduce contact stress and the resulting wear of the bearing surface. However, with mobile bearing designs, there is the possibility of the bearing becoming dislodged from the implant. Additionally, mobile bearing knee designs are more surgically demanding to implant then fixed bearing designs.
The combination of a fixed bearing insert for the medial compartment and a mobile bearing insert for the lateral compartment is particularly attractive because the lateral femoral condyle rolls backward on the lateral tibial plateau as much as 10 to 20 mm whereas the medial condyle moves only a few millimeters. A mobile bearing insert is able to accommodate the rollback of the lateral condyle but would not be necessary for the medial condyle.
Two primary difficulties exist with current joint replacement surgeries. These relate to the invasiveness of the procedure and achieving proper alignment of the bony structures and the prostheses thereupon.
Alignment
A difficulty with implanting both modular and non-modular knee implants having either separate femoral and/or tibial components has been achieving a correct relationship between the components. Surgical instruments available to date have not provided trouble free use in implanting multi-part implants wherein the femur and tibia are prepared for precise component-to-component orientation. While alignment guides aid in accurate orientation of the components relative to the axis of the long bones to achieve a restoration of a correct tibiofemoral alignment (usually 4-7 degrees valgus), they provide limited positioning or guidance relevant to correct component-to-component alignment and/or ligament tension to restore alignment.
It is preferable to orient implants normal to the resultant forces through the joint to subject bearing surfaces to compressive rather than shear forces. Moreover, the components of the implant are preferably oriented one to the other to minimize wear. Complications may result if the implant is not correctly oriented with respect to the supporting bone. If the implant is not placed normal to the mechanical axis, a shearing force results between the implant and bone that may lead to implant loosening.
In a properly aligned knee, the mechanical axis of the leg (a straight line drawn from the center of the hip joint to the center of the ankle) passes slightly medial to the center of the knee. This alignment is generally called the gross alignment of the leg. The alignment of the implants impacts the gross alignment of the leg. If the implants are malaligned, the resulting mechanical axis may be shifted medially or laterally, resulting in an imbalance in the loads carried by the medial or lateral condyles. This imbalance, if severe, may lead to early failure of the implant.
In addition, the orientation of the components to each other, for example the orientation of the femoral to the tibial component, with unicondylar and bicondylar implants has largely not been addressed. This may account for the high failure rates of early bicondylar designs and as well as for the higher failure rate of unicondylar implants relative to total knee implants as demonstrated in some clinical studies. When considering bicondylar and unicondylar designs, alignment of each part relative to the other parts is critical to avoid accelerated wear with a mal-articulation of the components.
Although various prosthetic devices have been successfully used with patients, the configuration and position of the articulating surfaces of the prosthesis, that is, for example, the condyles in a knee joint are predetermined based upon the prosthesis that is selected. While efforts are made to tailor the prosthesis to the needs of each patient by suitable prosthesis choice and size, this in fact is problematical inasmuch as the joint physiology of patients can vary substantially from one patient to another.
Invasiveness
In order to appropriately sculpt the articulating surface of a bone, it is often necessary to surgically expose the joint. In the case of the femur, the patellar tendon of the knee joint is surgically exposed and is moved to one side of the joint to enable a substantially full anterior access to the joint. Surgical exposure is necessary to accommodate the bulk and geometry of the components as well as the instruments for bone preparation. Such surgical exposure increases bleeding, pain, and muscle inhibition; all of which contribute to a longer hospitalization before the patient can be safely discharged to home or an intermediate care facility.
Desirably, in the case of knee replacement surgery, neither the collateral ligaments nor the cruciate ligaments are disturbed, although it is often necessary to remove or release cruciate ligaments in the event a substantial joint replacement is to be performed. Collateral ligaments can be partially taken down or released to provide appropriate tension adjustment to the patient""s knee in concert with joint replacement surgery. In most instances, such releases can be accomplished through smaller incisions than the standard midline or medial parapatellar incisions historically used for knee arthroplasty.
Arthroscopic surgery is available, and beneficial, for removing and repairing damaged intraarticular tissues. Although arthroscopic procedures are far less invasive and are often successful for minor surgical repairs, (as when an articular surface is to be smoothed, for example, or cartilage is to be repaired), such procedures generally are not appropriate for substantial joint replacement. They are generally inadequate for replacing joint surfaces with artificial implants.
Conventional surgical procedures including unicompartmental and total joint replacement historically require extensive surgical exposure and prolonged hospital stays and rehabilitation. More recently unicondylar procedures have been performed through smaller incisions that do not necessitate dislocation of the patella. The reduction in pain and more rapid recovery of knee function has reduced the length of hospital stay and the need for strong narcotic medications. It is desirable to realize such benefits for patients with bicompartmental and tricompartmental knee arthroplasty.
For patients who require articular surface replacement, including patients whose joints are not so damaged or diseased as to require whole joint replacement, it would be desirable to provide surgical methods and apparatuses that could be employed to gain surgical access to articulating joint surfaces, to appropriately sculpt the surfaces, to provide artificial, e.g., metal or plastic, articular bearing surfaces, and then to close the surgical site, all without substantial damage or trauma to associated ligaments and tendons. To reach this goal, of course, a procedure must be provided to enable articulating surfaces of the joints to be appropriately sculpted using minimally invasive apparatuses and procedures.
The present invention provides an implant system that restores individual patient joint kinematics and involves minimally invasive surgical procedures. The instruments and implants disclosed accomplish accurate bone and soft tissue preparation, implant orientation and implant fixation through limited surgical exposure. The implant system is comprised of implants and instrumentation that provide intraoperative surgical options for articular constraint and facilitate proper alignment and orientation of the knee to restore kinematics as defined by the individual patient anatomy. To do so, the implants provide a surgeon intraoperative options to reconstruct various degrees of joint stability via selection of fixed or mobile bearing components for each compartment of the knee (medial tibiofemoral joint, lateral tibiofemoral joint and patellofemoral joint). The range of implants may cover each compartment of the knee and may include combinations of fixed and mobile bearing configurations.
In traditional total knee replacements, the femoral component is generally a unitary piece and the tibial component is a unitary piece. In the current invention, the femoral side may be resurfaced by two or three components and the tibial side may be resurfaced by two components or a unitary piece. Optionally, the components of the femoral side may be comprised of a plurality of flexible segments.
Proper alignment and positioning of the implant components is facilitated by instrumentation that utilizes the soft tissue structures of the knee to guide bony resections for patient-specific alignment and orientation of the implants. The surgical instrumentation prepares the articular surfaces of a synovial joint from a single point of reference to allow the introduction of separate components for the medial and lateral tibiofemoral compartments, and the patellofemoral compartments with precise orientation. Thus, the instrumentation provides bony resections in accordance with such alignment and orientation requirements. The alignment positioning is important for proper restoration of anatomic alignment of the knee joint and for proper orientation of the components to one another.
With respect to forming or sculpting articular surfaces of a joint, the method of the current invention enables the articular bone surfaces to be sculpted according to the individual physiology of each patient to restore as much as possible the natural junction of the joint. In this method, a bone sculpting tool is attached to one of the bones of a joint, and the tool sculpts the articular surface of the other bone as the joint is articulated.
Thus, in one embodiment, the present invention provides a method of appropriately sculpting the articular surface of a first bone that normally articulates with a second bone. The method involves providing an apparatus comprising a bone sculpting tool attached to a bone mount, attaching the mount rigidly to the second bone with the tool in bone sculpting engagement with the articular surface of the first bone, and then sculpting the articular surface by articulating one of the bones with respect to the other.
In some situations, it may be desirable to distract the first bone from the second bone either preoperatively or during surgery. Thus, a distractor may be provided with the apparatus. A distraction force provided between the femur and the tibia during the sculpting procedure accounts for material that has worn away from the articular surfaces. Use of a distraction force generally re-establishes normal alignment of the joint. Additionally, a distractor may be used preoperatively to assess the range of motion of the joint and patient kinematics.
In another embodiment, the invention provides an apparatus for sculpting the articular surface of a first bone that normally articulates in a predetermined manner with the second bone. The apparatus comprises a bone sculpting tool, a mount attachable rigidly to the second bone, and an adjustable attachment attaching the sculpting tool to the mount and enabling the position and orientation of the tool to be adjusted into bone-sculpting proximity to the articular surface so that the articular surface is sculpted as the second bone is articulated with respect to the first bone. Alternately, a plurality of bone sculpting tools may be used where the tools are positioned either on individual mounts or on a single mount to support the plurality of tools.
The invention also provides implants for replacing the surfaces of the joint between the first bone and the second bone. The implants are specifically designed to fit through minimally invasive incisions and incorporates any and all combinations of fixed and mobile bearing inserts or parts. Since the surgical procedure preferably is performed through minimally invasive incisions the implants are designed to fit through such incisions and be either oriented or joined within the joint.
The implants include a second bone baseplate and a first bone implant. The second bone baseplate may be either one piece to cover most of the prepared surface of the second bone as relates to the joint, or separate baseplates as have been used with mobile and fixed bearing prosthetic components. In addition, the second bone baseplate may accommodate separate fixed and mobile bearing inserts. The first bone implant is comprised of a plurality of components to replace the bearing surface of the first bone. Optionally, a portion of the first bone implant may be configured of a plurality of flexible segments bonded in place. Such a configuration permits the articulation of the second bone to the first bone to mould the flexible segments in appropriate position.
Thus, in a further embodiment, the invention provides a method of appropriately replacing the articular surface of a first bone that normally articulates with a second bone. The method involves providing an apparatus comprising a bone sculpting tool attached to a bone mount, attaching the mount rigidly to the second bone with the tool in bone sculpting engagement with the articular surface of the first bone, and then sculpting the articular surface by articulating one of the bones with respect to the other. Further, resurfacing the articular surfaces with appropriate minimally invasive implants wherein the implants are joined within the confines of the joint cavity. In one embodiment, a plurality of flexible segments are provided to resurface a portion of the first bone. The flexible segments are set in an adhesive along the resected surface of the first bone.
Specifically, for example, the invention may be used for replacing the surfaces of a femur and a tibia. Thus, a femoral implant having a plurality of components and a tibial baseplate are provided. The tibial baseplate may have a fixed bearing attachment as well as a mobile bearing attachment.

Apparatus and method for sculpting the surface of a joint

c/o Alexandria Research Technology, LLC, 9409 Ludgate Dr.


A dual electric layer capacitor containing two electrodes of which one or both are polarizable, liquid electrolyte, and a separator. The degree of filling the pores of the separator and of both elements is between 40and and 90% of a total volume of the pores.

The invention relates to electrical engineering, in particular, to capacitor-making industry and can find application in producing high-capacity electric capacitors making use of double electric layer (DEL). Capacitors with DEL have found application as stand-by power sources in systems requiring uninterrupted power supply, such as computation engineering, communications equipment, numerically controlled machine tools, in uninterrupted cycle production processes; for electric-starter starting of diesel engines; for power supply of invalid carriages, golf carriages, etc.
Known in the art presently are electric energy accumulators appearing double electric layer (DEL) capacitors, e.g., those disclosed in U.S. Pat. No. 4,313,084 (1982) and 4,562,511 (1985). Said capacitors comprise each two porous polarizable electrodes and porous separator made of a dielectric material and placed therebetween, and current leads. A liquid electrolyte solution in the capacity of which either aqueous or non aqueous electrolytes are used (is contained in the pores of the electrodes and separator, as well in a certain free space inside the capacitor casing. Electric charge is accumulated on an interphase surface in the pores between the electrode material and the electrolyte. Used as the materials of polarizable electrodes are various routine porous carbon materials. To increase the capacitor capacitance with double electric layer said carbon materials are subjected to preactivation with a view to increasing their specific surface area up to 300-3000 sq.m/g.
DEL capacitors have much higher capacity compared with routine film-type and electrolytic capacitors, i.e., up to a few scores of Farads per gram of active electrode materials. However, such capacitors suffer from a rather specific energy, i.e., not more than 3 watt-hours/lit.
Another disadvantage inherent in DEL capacitors resides in evolving gases during recharging, e.g., oxygen on the positive electrode and/or hydrogen on the negative electrode. The fact is due to the fact that the potential of evolution of said gases on the respective electrodes is reached during recharging. The result is an increased pressure of the gases inside the capacitor casing which may lead to its depressurization and even blasting if no provision is made for a special pressure release valve. However, operating reliability of such valves is frequently inadequate to ensure against such depressurization or blasting due to their getting clogged with dirt, and so on. It is for said and other reasons that DEL capacitors suffer from a fundamental disadvantage, that is, a danger of their depressurization and even blasting which involves special service and maintenance thereof. To provide more reliable prevention of depressurization during recharging, one should considerably reduce the final charging voltage for the sake of xe2x80x9cdouble insurancexe2x80x9d, whence the initial discharge voltage is reduced, too so as not to approach a dangerous border-line. This in turn results in a considerable drop of the specific energy of the DEL capacitor which, as is commonly known, is directly proportional to the squared specific energy of the DEL capacitor which, as is commonly known, is directly proportional to the squared difference between the initial and final discharge voltage values.
Known in the present state of the art is a DEL capacitor (cf. WO 97/07518 of Feb. 27, 1997) having a polarizable electrode made of a porous carbon material, and a non-polarizable electrode made of nickel oxide. Used as electrolyte is an aqueous carbonate or hydroxide of an alkali metal. Such a capacitor gives much more specific energy value compared with a DEL capacitor having two polazable electrodes (up to 45 J/cu.cm or 12.5 W-h/lit), and a maximum voltage of 1.4 V. However, the capacitor described before yet suffers from substantial disadvantages, that is, the problem of how to provide its complete pressurization and need in special service and maintenance thereof. As a result of non-provision of a complete pressurization of the capacitor are reduced values of a maximum charging voltage and specific energy, as well as inadequately high charging current values and hence too long a charging time.
It is an object of the present invention to provide a completely pressurized servicexe2x80x94and attendance-free capacitor.
It is another object of the invention to enhance the specific energy of the capacitor and to reduce the charging time.
The foregoing objects are accomplished due to the herein-disclosed invention whose essence resides in that in a dual electric layer capacitor comprising two electrodes of which either one or both are polarizable, a liquid electrolyte, and a separator, the degree of filling the void space of the separator and of both electrodes with electrolyte falls within 90 and 40%.
The essence of the present technical solution resides in that gaseous oxygen liberated on the positive electrode of a DEL capacitor at the end of charging and during recharging is basically absorbable completely on the negative electrode during its ionization reaction (electric reduction) due to very high polarization of said reaction (Ep greater than 1 V) and due to the fact that the activated carbon is a very good catalyst for the process in question, whereby it is made use of in fuel cells (cf. xe2x80x9cChemical current sourcesxe2x80x9d by V. S. Bagotski and A. M. Skunden, Moscow, xe2x80x9cEnerghiaxe2x80x9d PH, 1981, pp. 80, 116 (in Russian). On the other hand, gaseous hydrogen which can be liberated on the negative electrode during recharging a DEL capacitor, can substantially be absorbed completely on the positive electrode during its ionization reaction (electric oxidation) due to a very high polarization of said reaction (Ep greater than 1 V). However, in routine DEL capacitors the pores of the separator and of both electrodes are filled with electrolyte virtually completely so that gas porosity in said porous bodies is virtually absent. Under such conditions very much trouble is encountered as regards diffusion as far as the transfer of the gases liberated during the charging and recharging procedures, from one electrode to the other is concerned. The point is that the mechanism of such a transfer consists in dissolving said gases in liquid electrolyte contained in the pores of the electrode, wherein it is generated, in its diffusing in a dissolved state over the flooded pores of said electrode, of the separator and of thee opposite electrode, the reaction of its ionization occurring not until said operations are completed. It is due to very low solubility of hydrogen and oxygen in liquid electrolytes under standard conditions and thereby very low corresponding value of the diffusion coefficient that the resultant ionization rate of said gases on the opposite electrodes with a virtually completely filled void space of the separator and of both electrodes is very low, too. Said rate is likewise as low even in cases where one or both electrodes feature certain gas porosity whereas the separator pores are footed completely. Very low rate of transfer of the gases between the electrodes is much less their generation rate during recharging, whereby the pressure inside the capacitor casing increases which is fraught with its depressurization and even with blasting.
An inventive concept underlying the present invention consists in that a single system of gas pores is established in a DEL capacitor throughout the entire electrochemical group (ECGp) thereof, comprising porous electrodes and a porous separator. Thus, oxygen and hydrogen gases which are liberated during capacitor charging and recharging are conveyed very rapidly along said system to the opposite electrodes whereon both gases undergo ionization to form water or respective ions (H+, OH, and others). The fact is that the diffusion coefficients of gases in the gaseous phase is four orders of magnitude higher than that in the liquid phase. Such a system of gas pores is provided due to the fact that the void space of both porous electrodes and the porous separator having a degree of filling of their pores within 90 and 40%. Hence the proportion of a non-filled void space of gas pores (gas porosity) in each of the porous body of the ECGp falls within 10 and 60%, with the result that the required system of gas pores is established. Further reduction of the degree of filling the ECGp with electrolyte is undesirable as fraught with an appreciable increase in the internal resistance of the capacitor.
To establish gas porosity can be provided by a variety of techniques, one of which being applicable whenever electrolyte is contained only in the pores of the electrodes and of the separator, i.e., when no free electrolyte is present in the capacitor. The definite values of a degree of filling the void space in the electrodes and separator in the aforementioned range from 90 to 40% of a total space is attainable, firstly, due to appropriately measuring out a full amount of electrolyte introduced into the capacitor, and secondly, by using electrodes and a separator with definite mutually coordinated porous structures. As a matter of fact, distribution of a liquid inside a system of mutually contacting porous bodies depends quantitatively on the size distribution curves (porograms) of the pores of said porous bodies. The nature of said quantitative dependence has been established in the following papers (cf. Volfkovich Yu. M. the Journal xe2x80x9cElektrokhimiaxe2x80x9d, 1978, v. 14, #4, p.546, vol. 14, #6, p.831; #10, p. 1477 (in Russian); Volfkovich Yu. M. and Bagotzky V. S. Power Sources, 1994, v. 48, pp. 327, 339). For instance, with an increased proportion of large pores in a separator compared with electrodes, the degree of filling the separator pores is decreased compared with said electrodes. Control over the execution of the preset values of the degree of filling of pores in each porous body of the ECGp may be carried out, firstly, by weighing the separator and electrodes both in a fully flooded stated (under vacuum) and following a working impregnation of the separator and electrodes, assembling the capacitor and its subsequent disassembling; and secondly, by taking the porograms of the electrodes and separator, as well as by weighing the entire ECGp before and after impregnation with electrolyte.
In order to fulfil the aforestated condition as to electrolyte containing only in the pores of the electrodes and of the separator, it is reasonable that one capacitor or a bank of capacitor elements be held between the load-bearing cover of the casing as otherwise the capacitor internal resistance is increased.
Another method for providing the required gas porosity of the electrodes and separator consists in that a dispersed water repellant is added to one or both electrodes and/or to the separator appearing as, e.g., polytetrafluoroethylene or polyethylene. Water-repellency treatment of the negative electrode increases the rate of diffusion of the electrolyte-dissolved oxygen inside the pores directly to the internal electrode/electrolyte interface and the resultant higher rate of its electric reduction. Insofar as capacitor recharging as a result of misoperation (with E less than 0 V) must not be ruled out completely, hydrogen is liable to evolve on the negative electrode. Adding a dispersed water repellant to the positive electrode accelerates abruptly the process of hydrogen transporting to the inner surface thereof and the resultant process of hydrogen electric oxidation on said electrode. Thus, adding water repellants to the composition of porous electrodes helps solving the problem of creating completely pressurized capacitor.